Text removed as no longer current.

Stuart

Is it an aluminum r brass rad?
Also, is the hole in a cooling tube or on one of the tanks, upper or lower?
Often a cooling tube can simply be pinched off to solve the problem. Loss of one cooling tube is usually not a big issue.
If you are soldering be careful about the amount of heat you introduce, use cold wet cloths in the adjacent area to act as heat sinks and work quickly.
The issue with to much heat is the possibility of creating a leak elsewhere due to other joints becoming unsoldered.
Good luck.

There are lots of Iltis parts around. If you have a spare or can find one for less than shop repair, maybe go that way. Then with the holed rad' on a bench you can try out the suggested repairs.

I will do repairs on tanks, but I generally leave core repairs to the pros. Rad repair is not an expensive proposition, and it is not a red seal trade. You have already done the expensive part which is the time consuming job of removing the rad.

The only thing which will possibly hurt is if the rad shop decides to tell you the core is getting thin, and they want to sell you a re-core. If so, take it to the next place. If you get three shops that tell you the same thing, then indeed itmay be time for a new core.

Re flushing engines. While you can remove debris and some sludge with a garden hose, (even better is the flushing attachments that use the garden hose and an airlline for short pressure bursts) but you won't get rid of scale buildup. For that, there are certain chemicals you can use, and some that will quickly destroy your water pump. If you remove the pump, cap the holes, remove your thermostat, some of de-scaler chemicals can be used in moderation, but any real length of time can eat at the head gaskets. If scaling has gone too far, the only real solution is to remove the engine, disassemble and have the block chemically cleaned.

Many of the Cdn tire products that are for rad flushing have to have the engine run to operating temps. So again, the old garden hose isn't going to do it.

Of course, as any Iltis owner knows, the Iltis are very particular about the antifreeze mixture. Too much antifreeze with less water results in them overheating....they need their 50/50 (or 60/40 mix out here on the prairies) mix to operate properly.

I had a chance to buy 5 rads for $80 at a surplus auction a few years ago. I passed. In hindsight, it would have been hard to go wrong at that price.